The present invention relates generally to a storage system, and more specifically to the storage and retrieval of data, such as metadata, in a storage system.
Disk storage is a general category of storage mechanisms in which data is digitally recorded by various electronic, magnetic, optical, or mechanical methods on a surface layer deposited on one or more planar, round and rotating disks (also referred to as “media” or “storage devices”). A disk drive is a device that is used to implement such a storage mechanism with fixed or removable media.
Storage systems that include multiple storage devices typically utilize metadata to describe the mapping between user data and physical data. On large and complex storage systems with hundreds of storage devices and complex data layouts, the metadata is often voluminous (e.g., multiple Gigabytes or “GBs”). In order to access the data on the storage devices, metadata that describes the mapping between user data and physical data has to be stored in a manner that is as least as reliable as the storage of the data.
In contemporary storage systems, the storage of the metadata is optimized for either good write performance or for good read performance. Thus, in order to maximize efficiency (e.g., speed), a tradeoff is made between the efficiency of writing to the storage device and the efficiency of reading from the storage device.